JPH0871970A - Control device for robot - Google Patents

Abstract

PURPOSE: To prevent a servomotor from vibrating when a robot retains a stop position where the robot comes to a stop. CONSTITUTION: A control device for a robot is composed of a hand part moving and resting means for moving a hand part to an arbitrary position and resting the same at this position, a hand part resting position retaining means 4 for holding the hand part at the resting position when the hand part moving and resting means confirm the resting of the hand part, a motor shaft fixing means 5 for fixing the shaft of a servo motor when the hand part resting position retaining means 4 confirms the holding of the hand part at the resting position, and a motor power cut-off means 6 for cutting off power fed to the servo motor when the motor shaft fixing means 5 confirms the fixing of the shaft of the servo motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot controller provided with a servo motor which is connected to a hand unit and drives the hand unit, and a brake which enables the axis of the servo motor to be fixed or released.

[0002]

2. Description of the Related Art The structure and operation of a conventional robot system will be described with reference to FIGS. FIG.
FIG. 6 is a basic block diagram for holding the hand unit in an arbitrary position and holding the hand unit in that position in the related art. FIG. 9 is a basic block diagram for re-moving the hand unit held and held in FIG. Figure 10
It is a basic block diagram at the time of emergency stop. FIG. 11 is a block diagram showing a conventional robot and control device. FIG. 12 is a flow chart for holding and holding the conventional hand unit. 13 is the same as FIG.
It is a flowchart figure for moving the hand part which was made to stand still by 2 and was made to hold | maintain again.

In FIG. 8, the hand unit still position holding command means 1 causes the hand unit to stand still at an arbitrary position, and a signal of a hand unit still position holding command for holding the hand unit at that position is input to the control unit 40. Then, the control unit 40 outputs a signal for moving the hand unit and stopping it at an arbitrary position to the hand unit moving / stationary unit 3. Next, the control unit 40 outputs a signal for holding the position where the hand unit is stationary to the hand unit stationary position holding unit 4.

In FIG. 9, a signal of a hand part movement command for moving the held hand part again by the hand part movement start command means 7 is input to the control means 41. Then, the control means 41 releases the holding of the position where the hand portion is stationary, moves the hand portion again, and outputs a signal for performing an arbitrary operation to the axis movement starting means 11.

In FIG. 10, the emergency stop command output from the emergency stop command means 42 is input to the control means 43.
Then, the control means 43 outputs a signal for fixing the axis of the servo motor to the motor shaft fixing means 5. next,
The control means 43 outputs a signal for cutting off the power supply to the servomotor to the motor power cutoff means 6.

In FIG. 11, a robot 12 includes a hand portion 13 composed of a movable slider, a servo motor 14 connected to the hand portion 13 for moving the hand portion 13, and a servo motor 14. A brake 15 for fixing or releasing the shaft and a rotation / position detecting device 16 for detecting the number of rotations and the position of the hand portion 13 are provided. The control device 17 includes a motor drive unit 18 that drives the servomotor 14, a brake drive unit 19 that controls whether to supply or cut off electric power to the brake 15.
A storage unit 20 in which an operation pattern or the like of the hand unit 13 is stored in a ROM or a RAM, and a signal input from the storage unit 20, the rotation / position detection device 16, the external device 22, and the like, the motor drive unit 18, the brake. The control unit 21 for controlling the drive unit 19 is provided. The power supply unit 45 supplies electric power to the brake drive unit 19, the motor drive unit 18, the control unit 21, the rotation / position detection device 16, etc. by converting them into arbitrary voltages.

When electric power is supplied to the brake 15, the brake 15 opens the axis of the servo motor 14. When the power is cut off, the brake 15
The axis of the servo motor 14 is fixed. Therefore, the hand unit 1
By fixing 3 the hand part 13 is prevented from falling and moving.

When the hand unit 13 is to perform an arbitrary operation, the control unit 21 inputs the operation pattern stored in the storage unit 20 from the storage unit 20 and outputs it as a motor control signal 21b to the motor drive unit 18. . Then, the motor drive unit 18 drives the servo motor 14 based on the input motor control signal 21b, and causes the hand unit 13 to perform an arbitrary operation.

When the power supply is turned off, the power supplied to the power supply unit 45 is cut off. That is, the motor drive unit 1
8. The power supply to the brake drive unit 19 is cut off, the winding of the servo motor 14 is not excited, and the brake 15 fixes the axis of the servo motor 14 to prevent the hand unit 13 from falling and moving. To do.

A case in which the hand portion 13 is stopped at an arbitrary position and held at that position will be described with reference to FIGS. 8, 11, and 12.

As the hand unit stationary position holding command means 1,
An external device 22 such as a teaching pendant outputs a hand part rest position holding signal 21e, that is, a hand part rest position holding command to the control part 21. Alternatively, a program in the storage unit 20 outputs a hand unit stationary position holding command to the control unit 21. Then, as the control means 40, the following motor control signal 21 is sent from the control unit 21 to the motor drive unit 18.
Output b.

When the motor control signal 21b is output from the control section 21 to the motor drive section 18, first, the motor drive section 18 as the hand section moving / stationary means 3 starts from step c1.
The operation of step c3 is performed. That is, in step c1, while decelerating the servo motor 14, the hand unit 13
Move to a rest position. Then, in steps c2 and c3, the positioning is completed while the position is corrected by the rotation / position coordinate signal 21a output from the rotation / position detection device 16. Next, as the hand portion stationary position holding means 4, the motor drive portion 18 performs the operation of step c4. That is, in step c4, when the positioning is completed, the servo motor 14 is servo-locked, and the hand unit 13 is held at an arbitrary stationary position.

Further, even after the holding, the servo motor 14 constantly performs the position correction in order to hold the stationary position. By performing the above steps, the hand unit 13 is stopped at an arbitrary position and held at that position.

A case in which the hand portion 13 is moved again from the stationary / holding position will be described with reference to FIGS. 9, 11, and 13.

As the hand part movement start command means 7, an external device 22 such as a teaching pendant outputs a hand part movement signal 21f, that is, a hand part movement command to the control part 21. Alternatively, a hand movement command is output to the control unit 21 from a program in the storage unit 20. And the control means 4
1, the following motor control signal 21b is output from the control unit 21 to the motor drive unit 18.

When the motor control signal 21b is output from the control section 21 to the motor drive section 18, the motor drive section 18 as the axis movement starting means 11 performs the operation of step c6. That is, in step c6, the servo lock is released, the servo motor 14 is moved again, and the hand unit 13 is caused to perform an arbitrary operation.

The operation when an emergency stop is performed will be described with reference to FIGS.

As the emergency stop command means 42, an emergency stop device 21 such as an emergency button outputs an emergency stop signal 21c, that is, an emergency stop command to the control section 21. Then, as the control means 41, the control unit 21 outputs a motor control signal 21b to the motor drive unit 18, and the control unit 21 outputs a brake control signal 21d to the brake drive unit 19.

When the motor control signal 21b is output from the control unit 21 to the motor drive unit 18, the motor power cutoff means 6
As a result, the motor driving unit 18 shuts off the electric power supplied to the servo motor 14. Further, when the brake control signal 21d is output from the control unit 21 to the brake drive unit 19, the brake drive unit 19 serves as the motor shaft fixing means 5.
Fixes the shaft of the servomotor 14 with the brake 15.

[0020]

As described above, in the conventional control device, the servo lock is performed to hold the stationary position of the hand portion. However, in order to maintain this position, position correction must always be performed. At this time, if the position of the hand part is constantly changing due to load, external action, etc.,
The position correction is repeated, which causes the servomotor to vibrate.

[0021]

SUMMARY OF THE INVENTION Therefore, according to the present invention, when the hand unit moving / stationary means for moving the hand unit to stop the hand unit at an arbitrary position and the hand unit's stationary state are confirmed by the hand unit moving / stationary means, When the hand portion stationary position holding means for holding the hand portion in the stationary position and the holding of the hand portion stationary position by the hand portion stationary position holding means are confirmed, the motor shaft fixing means for fixing the shaft of the servo motor, and the motor A controller for a robot, comprising: a motor power cutoff means for cutting off the power supplied to the servomotor when the fixation of the axis of the servomotor is confirmed by the axis fixing means.

Alternatively, when the holding of the stationary position of the hand unit is confirmed by the holding unit for the stationary position of the hand unit, the counting unit for counting the stationary time of the hand unit, the time setting unit for setting an arbitrary time, and the time setting unit. When the time counted by the counting means is longer than the time set by the time setting means, the comparing means compares the difference between the time set by and the time counted by the counting means. A motor shaft fixing means for fixing the axis of the servo motor, and the motor power cutoff means for cutting off the power supplied to the servo motor when the fixation of the servo motor axis is confirmed by the motor shaft fixing means. A control device is provided.

[0023]

According to the first aspect of the present invention, when the command to hold the hand rest position is input to the control unit, the servo motor decelerates and starts moving to the rest position, and the rotation / position output from the rotation / position detection device is output. The hand unit is stopped at the stationary position while the position is corrected by the coordinate signal. Then, when it is confirmed that the hand unit is stationary, the control unit outputs a brake control signal for cutting off the supply of electric power to the brake to the brake drive unit, and the brake fixes the axis of the servo motor. Next, a motor control signal for cutting off the supply of electric power from the control unit to the winding of the servo motor is output to the motor driving unit, and the winding of the servo motor is no longer excited.

In the second aspect, when the hand unit stationary position holding command is input to the control unit, the servo motor decelerates and starts moving to the stationary position, and the rotation / position output from the rotation / position detection device. The hand unit is stopped at the stationary position while the position is corrected by the coordinate signal. When the stationary state is confirmed, the counting unit starts counting time. Then, the control unit compares the difference between the arbitrary time preset in the time setting unit and the time counted in the counting unit, and when the time of the counting unit becomes longer than the time set in the time setting unit. A brake control signal for cutting off the supply of electric power from the control unit to the brake is output to the brake drive unit, and the brake fixes the axis of the servo motor. Next, a motor control signal for cutting off the supply of electric power from the control unit to the winding of the servo motor is output to the motor driving unit, and the winding of the servo motor is no longer excited.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a basic block diagram for holding the hand unit at an arbitrary position and holding the hand unit in the first embodiment of the present invention. FIG. 2 is a basic block diagram for re-moving the hand unit held and held in FIG. FIG.
It is a flow chart figure for making a hand part stand still and to hold in a 1st example of the present invention. FIG. 4 shows FIG.
It is a flowchart figure for moving the hand part which was made to stand still and was hold | maintained again.

In FIG. 1, the hand portion stationary position holding command means 1 causes the hand portion to stand still at an arbitrary position, and a signal of a hand portion stationary position holding command for holding the hand portion at that position is input to the control means 2. Then, from the control means 2,
A signal for moving the hand unit and stopping it at an arbitrary position is output to the hand unit moving / stationary unit 3. Next, the control unit 2 outputs a signal for holding the position where the hand unit is stationary to the hand unit stationary position holding unit 4. Next, the control means 2 outputs a signal for fixing the axis of the servo motor to the motor shaft fixing means 5. Next, the control means 2 outputs a signal for shutting off the power supplied to the servomotor to the motor power shutoff means 6.

In FIG. 2, a signal of a hand part movement command for moving the held hand part again by the hand part movement start command means 7 is input to the control means 8. Then, the control means 8 supplies power to the servo motor,
A signal for servo-locking the position where the hand portion is fixed and holding the position is output to the motor power supply means 9. Next, the control means 8 outputs a signal for opening the shaft of the servo motor to the motor shaft opening means 10. Next, the control unit 8 outputs the signal for moving the hand unit again and performing an arbitrary operation to the hand unit movement starting unit 11.

The robot and the control device according to the first embodiment of the present invention have the same structure as in FIG. 11 in the prior art. The robot 12 includes a hand portion 13 composed of a movable slider and the like. A servo motor 14 connected to the hand portion 13 to move the portion 13;
A brake 15 for fixing or releasing the axis of the servo motor 14 and a rotation / position detecting device 16 for detecting the number of rotations and the position of the hand portion 13 are provided. The control device 17 includes a motor drive unit 18 that drives the servo motor 14.
And a brake driving unit 19 that determines and controls whether to supply or cut off electric power to the brake 15, a storage unit 20 that stores an operation pattern of the hand unit 13 in a ROM or a RAM, and the storage unit 20. A control unit 21 for controlling the motor drive unit 18 and the brake drive unit 19 based on signals input from the rotation / position detection device 16 and the external device 22.
It has a structure of.

A case where the hand unit 13 is stopped at an arbitrary position and held at that position will be described with reference to FIGS. 1, 3, and 11.

As the hand portion stationary position holding command means 1,
An external device 22 such as a teaching pendant outputs a hand part rest position holding signal 21e, that is, a hand part rest position holding command to the control part 21. Alternatively, a program in the storage unit 20 outputs a hand unit stationary position holding command to the control unit 21. Then, as the control means 2, the following motor control signal 21b is sent from the control unit 21 to the motor drive unit 18.
In addition, the control unit 21 outputs the following brake control signal 21d to the brake drive unit 19.

When the motor control signal 21b is output from the control section 21 to the motor drive section 18, first, the motor drive section 18 as the hand section moving / stationary means 3 starts from step a1.
The operation of step a3 is performed. That is, in step a1, the hand unit 13 is decelerated while decelerating the servo motor 14.
Move to a rest position. Then, in steps a2 and a3, the positioning is completed while the position is corrected by the rotation / position coordinate signal 21a output from the rotation / position detection device 16. Next, as the hand portion stationary position holding means 4, the motor drive portion 18 performs the operation of step a4. That is, in step a4, when the positioning is completed, the servo motor 14 is servo-locked to hold the hand unit 13 at an arbitrary stationary position.

Next, the control unit 21 to the brake drive unit 19
The brake control signal 21d is output to the brake drive unit 19 as the motor shaft fixing means 5 to perform the operation of step a5. That is, in step a5, the brake 15 is operated to fix the shaft of the servo motor 14.

Next, the motor control signal 21b is output from the control unit 21 to the motor drive unit 18, and the motor drive unit 18 as the motor power cutoff means 6 performs the operation of step a5. That is, in step a6, the electric power supplied to the servomotor 14 is cut off. Also, the servo lock is released by cutting off the power. By performing the above steps, the hand unit 13 is stopped at an arbitrary position and held at that position.

A case where the hand unit 13 is moved again from the stationary / holding position will be described with reference to FIGS. 2, 4, and 11.

As the hand part movement start command means 7, an external device 22 such as a teaching pendant outputs a hand part movement signal 21f, that is, a hand part movement command to the control part 21. Alternatively, a hand movement command is output to the control unit 21 from a program in the storage unit 20. And control means 8
As a result, the control unit 21 outputs the following motor control signal 21b to the motor drive unit 18, and the control unit 21 outputs the following brake control signal 21d to the brake drive unit 19.

When the motor control signal 21b is output from the control section 21 to the motor drive section 18, first, the motor drive section 18 as the motor power supply means 9 performs the operation of step a7. That is, in step a7, the servo motor 1
4 is supplied with electric power to servo-lock the servo motor 14.

Next, from the control unit 21 to the brake drive unit 19
When the brake control signal 21d is output to the motor shaft opening means 10, the brake drive unit 19 operates as the motor shaft opening means 10.
8 operation is performed. That is, in step a8, the axis of the servo motor 14 is released from the brake 15.

Next, when the motor control signal 21b is output from the control unit 21 to the motor drive unit 18, the motor drive unit 18 as the axis movement starting means 11 performs the operation of step a9. That is, in step a9, the servo lock is released, the servo motor 14 is moved again, and the hand unit 13 is caused to perform an arbitrary operation.

The second embodiment of the present invention is shown in FIGS.
And it demonstrates using FIG. FIG. 5 is a basic block diagram for holding the hand unit at an arbitrary position and holding the hand unit in the second embodiment of the present invention. FIG. 6 is a block diagram showing a robot and a controller in the second embodiment of the present invention. FIG. 7 is a flow chart for holding and holding the hand unit in the second embodiment of the present invention.

In FIG. 5, the hand unit still position holding command output from the hand unit still position holding command unit 1 is input to the control unit 26. Then, the control unit 26 outputs a signal for stopping the hand unit to an arbitrary position to the hand unit moving / stationary unit 3. Next, the control means 26 outputs a signal for holding the position where the hand portion is stationary to the hand portion stationary position holding means 4. Next, the counting means 27 counts time, outputs the signal of this time to the comparing means 28, the time setting means 29 sets an arbitrary time, and outputs the signal of this time to the comparing means 28. To do. Next, when the time counted by the counting means 27 becomes longer than the time set by the time setting means 29,
A signal is output from the comparison means 28 to the control means 26.
Next, the control means 26 outputs a signal for fixing the axis of the servo motor to the motor shaft fixing means 5. next,
The control means 26 outputs a signal for shutting off the power supplied to the servomotor to the motor power shutoff means 6.

Before the time counted by the counting means 27 becomes longer than the time set by the time setting means 29, the hand movement command is issued by the hand movement start command means 7 as in the conventional example in FIG. Is input to the control means 26, the control means 26 releases the holding of the position where the hand portion is stationary, re-moves the hand portion, and sends a signal for performing an arbitrary operation to the axis movement starting means 11. Output to.

In FIG. 6, the robot 12 is provided with a hand unit 13, a servomotor 14, a brake 15, and a rotation / position detecting device 16, as in the conventional example. The control device 30 includes a motor drive unit 18 and
A brake drive unit 19 and a storage unit 20 are provided, and further,
A time setting unit 31 that sets an arbitrary time, a counting unit 32 that starts counting time after holding the servo motor,
The motor drive unit 18 and the brake drive unit 19 are controlled, and the time set by the time setting unit 31 and the counting unit 3 are controlled.
The control unit 33 compares the times counted in 2.

A case in which the hand portion is stopped at an arbitrary position and held at that position will be described with reference to FIGS. 5, 6, and 7.

As the hand portion stationary position holding command means 1,
An external device 22 such as a teaching pendant outputs a hand unit stationary position holding signal 33e, that is, a hand unit stationary position holding command to the control unit 33. Alternatively, a program in the storage unit 20 outputs a hand unit stationary position holding command to the control unit 33. Then, as the control means 26, the following motor control signal 33 is sent from the control unit 33 to the motor drive unit 18.
b is output, and the brake drive unit 19 is output from the control unit 33.
Then, the following brake control signal 33d is output.

When the motor control signal 33b is output from the control section 33 to the motor drive section 18, first, the motor drive section 18 as the hand section moving / stationary means 3 starts from step b1.
The operation of step b3 is performed. That is, in step b1, the hand unit 13 is decelerated while decelerating the servo motor 14.
Move to a rest position. Then, in steps b2 and b3, the positioning is completed while the position is corrected by the rotation / position coordinate signal 33a output from the rotation / position detection device 16. Next, as the hand unit stationary position holding unit 4, the motor drive unit 18 performs the operation of step b4. That is, in step b4, when the positioning is completed, the servo motor 14 is servo-locked and the hand unit 13 is fixed at an arbitrary stationary position.

Next, the counting means 27 and the time setting means 2
9 and the comparison means 28 perform the operation of step b5. That is, the counting unit 27 serves as the counting unit 32.
Starts counting the time when it confirms that the hand unit is stationary. Then, as the time setting means 29, the time setting unit 3
In 1, an arbitrary time is set. Also, the comparison means 2
As 8, the control unit 33 compares the time counted by the counting unit 32 with the time set by the time setting unit 31.

When the time counted by the counting unit 32 becomes longer than the time set by the time setting unit 31, the brake control signal 3 is sent from the control unit 33 to the brake drive unit 19.
3d is output, and the brake drive unit 19 as the motor shaft fixing means 5 performs the operation of step b6. That is, in step b6, the brake 15 is operated to fix the shaft of the servo motor 14.

Next, the motor control signal 33b is output from the control unit 33 to the motor drive unit 18, and the motor drive unit 18 as the motor power cutoff means 6 performs the operation of step b7. That is, in step b7, the electric power supplied to the servo motor 14 is cut off. Also, the servo lock is released by cutting off the power. By performing the above steps, the hand unit 13 is stopped at an arbitrary position and held at that position.

When a hand movement command is output to the control unit 33 within the time set by the time setting unit 31, the time counted by the counting unit 32 is output to the axis movement starting means 11 as in the conventional example. As a result, the motor drive unit 18 performs the operation of step b9. That is, in step b9, the servo lock is released, the servo motor 14 is moved again, and the hand unit 13 is caused to perform an arbitrary operation.

When the hand portion 13 is stopped at an arbitrary position, the brake 15 is operated, the electric power of the servo motor 14 is cut off, and the hand portion 13 is moved again, the same operation as in FIG. 4 in the first embodiment is performed. Make it work.

In the first and second embodiments, when a power-off command such as an emergency stop is input to the control device or the power is turned off, the brake 15 causes the axis of the servomotor 14 to rotate, as in the conventional example. Is fixed to prevent the hand portion 13 from dropping and moving.

In the first embodiment, a stationary command is input to the robot 12 and the servomotor 14 stops, and at the same time, the brake 15 fixes the axis of the servomotor 14. That is, it is used when there is a possibility that the supporting servomotor 14 will remain stationary for a long time if the servomotor 14 is stationary. In the second embodiment, when the stationary command is input to the robot 12 and the servomotor 14 is stationary, it is set in advance. The servo is locked for an arbitrary time, and when the set time is exceeded, the axis of the servo motor 14 is fixed by the brake 15. That is,
It is used when moving and stationary are repeated.

As described above, in the present invention, when the hand portion is stationary and held, in the present invention, after the servo lock, the brake is used to fix the axis of the servo motor and shut off the power to the servo motor. It is possible to prevent the conventional vibration.

[0054]

According to the present invention, the vibration due to the servo lock does not occur when the hand portion is stopped and held at an arbitrary position. Further, since power is not supplied to the servo motor, energy is saved.

[0055]

[Brief description of drawings]

FIG. 1 is a basic block diagram for holding a hand unit at an arbitrary position and holding the hand unit in the first embodiment of the present invention.

FIG. 2 is a basic block diagram for re-moving the hand unit that is stationary and held in FIG.

FIG. 3 is a flowchart for holding and holding the hand unit in the first embodiment of the present invention.

FIG. 4 is a flow chart diagram for re-moving the hand unit held and held in FIG.

FIG. 5 is a basic block diagram for holding the hand unit at an arbitrary position and holding the hand unit in the second embodiment of the present invention.

FIG. 6 is a block diagram showing a robot and a control device according to a second embodiment of the present invention.

FIG. 7 is a flow chart for holding and holding the hand unit in the second embodiment of the present invention.

FIG. 8 is a basic block diagram for holding a hand unit at an arbitrary position and holding the hand unit at the position in the related art.

9 is a basic block diagram for re-moving the hand unit that is held still in FIG. 8 and held.

FIG. 10 is a basic block diagram at the time of emergency stop.

FIG. 11 is a block diagram showing a conventional robot and control device.

FIG. 12 is a flow chart for holding and holding a conventional hand unit.

FIG. 13 is a flow chart for moving the hand unit that is stationary and held in FIG. 12 again.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hand part stationary position holding command means 2, 8, 26, 40, 41, 43 ... Control means 3 ... Hand part moving / stationary means 4 ... Hand part stationary position holding means 5 ... Motor shaft fixing means 6 ... Motor power interruption means 7 ... Hand part movement start command means 9 ... Motor power supply means 10 ... Motor shaft opening means 11 ... Axis movement start means 12 ... Robot 13 ... Hand part 14 ... Servo motor 15 ... Brake 16 ... Rotation /
Position detection device 17, 30 ... Control device 18 ... Motor drive unit 19 ... Brake drive unit 20 ... Storage unit 21, 33 ... Control unit 22 ... External device 27 ... Counting means 28 ... Comparison means 29 ... Time setting means 31 ... Time setting Part 32 ... Counting part 42 ... Emergency stop command means 44 ... Emergency stop device 45 ... Power supply part

Claims (2)

[Claims] 1. A robot controller having a servo motor for driving a hand unit, which is connected to the hand unit, and a hand unit moving and stopping means for moving the hand unit and stopping the hand unit at an arbitrary position. When the stationary portion of the hand portion is confirmed by the unit moving and stationary means, the hand portion stationary position holding means for holding the hand portion at this stationary position and the holding of the stationary position of the hand portion by this hand portion stationary position holding means A motor shaft fixing means for fixing the motor shaft; and a motor power cutoff means for cutting off the power supplied to the servomotor when the fixing of the servomotor shaft is confirmed by the motor shaft fixing means. Robot controller. 2. When the holding of the stationary position of the hand unit is confirmed by the hand unit stationary position holding unit, the counting unit for counting the stationary time of the hand unit, the time setting unit for setting an arbitrary time, and the time setting unit. Comparing means for comparing the difference between the time set by the above-mentioned time and the time counted by the counting means, and when the time counted by the counting means becomes longer than the time set by the time setting means by the comparing means. A motor shaft fixing means for fixing the axis of the servo motor, and the motor power cut-off means for cutting off the power supplied to the servo motor when the fixation of the servo motor axis is confirmed by the motor shaft fixing means. The control device for a robot according to claim 1, wherein: